Safety roller mechanism for use in watch movement escapes



Feb. 20, 1951 J. G. BISHOP SAFETY ROLLER MECHANISM FOR USE IN WATCH MOVEMENT ESCAPES Filed July 22, 1949 wwww l. Wa

Jzzson Glen flisfiop Patented Feb. 20, 195T UNITED S OFFICE SAFETYROLLER ME CHANISMJFOBIUSTE IN 5 MOVEMENT: ESCA Jason. Glenn Bishop,, vColumbus,10hio Applicationzluly2251949, Serial No. 106,148

5 Claims." (Cl. 585-122)" eror disk having a jewel projectinglaterally from its periphery which engages. with; forked; tinesformed on the end of-thepalletlever;opposite to that engaged :withthe escapement WhBBLzWhBIBr by, to' enable the -pallet-lever to. turn: about its: arbor. to a degree regulatedgby spacedistatione.

ary banking stops .or pins; .to;-thereby releaserandr.

lock in timed sequence thegmain' spring driven escapement wheel.

To prevent undesired-movement of the pallet:- lever between its banking stops, 'particul-arly'when the watch movement is, subiectedto shockssoin; jars, itzis thepresent practice to provide the; forked end of thepallet lever thatwis; the-pend"? disposed adjacent-to therbalanceqwheelt with'a rigid longitudinally pr jecting' guard finger-atria latterhein disposedin a planeoffset laterally to; that of the pallet lever and spaced fromthe collet roll-er jewel. The end of .the guard fingenis nor.- mally spaced from the peripheraL surfacexof: a:.. safety roller, the latter being positioned: on: the. a ba ance wheel staff in spaced relationifrom the; collet roller; The-slight clearance. provided-bee tween theouter end of the rigid-guardfinger ands: the peripheral surface. of the safety-roller is :pro'-.. vided to avoid friction betweenrelatively movable parts, but when the movement isjarred .orsshake, en, any motion of the pallet'leverraway .from'an: associated-banking pinor stop, is arrested by. di-il rect contact of the outer end otthe. guardrfingera with the. periphery of the; safetyxroller: This roller; however, is formed-with 'a peripheralrecess:

or notch whichzenables the, pallet leverrto mover freely without restraining action: onthe; part of? the safetyrcller when said; lever atproper: times.

is causedhy the: action "ofithelifting surfaces of the escapementzwheel teethto oscillaite'between the spaced banking pins;-

The-laterallyoffset guardfinger on the pallet lever and its associated safety roller comprise devices which increase the..thickness .of a watch movement, and. introduce mechanical complica--:,

time, added costs and other undesirable-con-dio 0 tions-and' alsoctthe cooperating-parts shouldibe.

butslightly misaligned, a possible, source of .m rs.

chanical disorder isoften presented.

It. is v.anohject of theinvention to provide. a

more efficient, simple. and practical guard finger v and. safety roller constructienforwatch move.-.. ments. thanhasbeen hitherto employed in the artl Itzis another .object of the invention. to provide an. improvedsafety roller construction for. watch,

movementa-includinga cooperative pallet. levercarriedguard finger, in which the roller is formed witlranarcuate guide, extending inwardly. from itsv peripheral edge, for cooperation with the outer.

end :ofthe guard finger,

Itisa. further object. of the invention to provide- 1. a safety roller. and guardfinger construction in which a thin compact design is affo1ded.wellsuit.-.-.

eds-for modern watch construction,

Itis anothercbject of the invention to provide the escapev movement of. a watch to. include .a

safety roller. having guide surfacesformed theree on-for engagement with a guard finger constitut-,

ing an extension of an oscillatory pallet lever, and

wherein thev guidesurfaces. include merging cir:

cular. and convolute regions. which, while,.pr0vid-.. ing for, closeassociation of. the guard fingerwith. said surfaces, nevertheless permit of the required.

freedom of turning movement of the safetyroller,

in unisonwith the staifjof the balance wheel,.

while. the pallet, lever is relatively stationarily-positioned in engagement with oneor the. other, of its bankingv stops.

Stillianother object of the invention is to pro-.

vide .a safety roller mechanism for watch movements characterized by. its long life, structural, simplicity and freedom from mechanical disorder.

For. a further understanding of the invention,

reference is. to be had to the following, descrip- Fig.2 is; asimilarfragmentary view disclosing the pallet lever andthe safetyrollerof the escape, mechanism, in difierent positions, of .op.eratio,n,,

from..those disclosed .in Fig.1;

Fig.3 is a fragmentary vertical sectionalview taken through the movement;

Fig; 4 is a lan view. of. a .collet disk or roller formed in accordancewith the presentinvention. Referring more particularly to the, drawings, the: numerahi designates. the. escape, wheel of a watch er other similar movement. The escape.

wheel.v includes .theusnai huh. 2 which issecuredto a, rotatable mainspringedriven,shaft The. wheel 1 is ,formed peripherally with the.. usual. circumferentially spaced tangentially. extending.

teeth 4 having. outer lifting surfaces 5. f

Carried'Joy the. frame a of the movementis an. arbor. 1' upon.which.ismmountedlioroscillation about the axis of the arbor a pallet lever 8. The lever at one end is formed with a yoke 9 which carries a pair of spaced pallet stones or jewels [0, the latter being provided with lifting surfaces ll complemental to those of the teeth 4 of the escape wheel. The pallet lever is rocked at intervals by the lifting action of the surfaces 5 and II and its rocking action is confined, as usual, by means of banking stops or pins 12, which may be eccentrically mounted on set screw bases 12' carried by the movement frame.

The outer end of the pallet lever is formed with the usual fork l3 having spaced tines [4 formed with reversely beveled surfaces 5 for cooperation with a roller jewel 16 which projects rigidly and perpendicularly from a disk roller II. The latter is mounted on the shoulder Ila of a collet hub llb, which, in turn, is located on the staff It of a hairspring-actuated balance wheel IS, the ends of the staff being attenuated and supported in cap jewels 20 of the movement frame. The hair spring Illa has its inner end connected with the hub 29a and its outer end with the wheel [9. As the balance wheel oscillates about the longitudinal axis of the staff [8, the collet disk or roller ll moves in unison therewith and likewise the roller jewel Hi. This jewel is engaged first by one of the tines l4 and then the other, thus oscillating the collet roller I! and the balance wheel iii in accordance with the rocking action of the pallet lever 8.

In order to protect the pallet lever against accidental displacement, particularly when the movement is subjected to shock and jar, the present invention provides on one side of the forked end of the pallet lever an extending arm or guard finger 22, the outer end of said finger being formed to provide a lateral pin or stud 23. The stud is positioned normally in slightly spaced order from the circular peripheral surface 24 of the disk ll.

To provide for free oscillating movement of the pallet lever 8 and finger 22, when aid pallet lever responds to the lifting action of the teeth 4 of the escape wheel, the disk or roller l1 includes an arcuate slot, groove or guide 26 which merges with the circular peripheral surface 24 of the disk. The guide 26 has as its center the pallet arbor I. By reference to Fig. 1, it will be noted that the stud 23 of the sprin arm is disposed at the inner end of the arcuate guide 26, a position which it occupies after the pallet lever has oscillated from the banking pin shown at the right of Fig. l to engagement with the banking pin shown at the left of Fig.

0n the oscillating return of the jewel [5 from the position which it occupies, as illustrated in Fig. to the position shown in Fig. 2, the said jewel i6 is contacted by the pallet lever fork and thereby serving in a manner causing it to assume the operating position disclosed in Fig. 2. In this operation, the necessary movement of the pin or stud 23 takes place without friction, since the' stud moves in and out of the groove or slot. 26 and around the circular surface of the roller 25, without contacting these surfaces unless the movement is jarred, and then the contact is but momentary.

With the construction described, the pallet lever is capably protected against jar and shock, and a simple and compact grouping of parts is provided adapted for thin watch construction. While the disk I! has been shown as being separately formed from the shouldered hub llb, these parts may be integrally formed, if desired. Other mechanical changes of a similar nature may be made within the scope of the invention.

I claim:

1. In an escapement mechanism for watch movements, a mainspring-driven escape wheel, an oscillatory pallet lever formed at one end with a yoke having engagement with teeth provided on the periphery of the escape wheel, the opposite end of said lever being formed with spaced tines, spaced stationary banking stops limiting rocking movement of said pallet lever, a balance wheel staff, a circular disk roller movable in unison with said staff, a jewel pin on said roller arranged for alternate engagement with the tines of said 'pallet lever, said roller being formed with an ar'cuate guideway extending inwardly of the roller from its circular outer edge across one face of the roller to its central region about said staff, and a guard finger formed on the outer end of said pallet lever movable in said guideway during oscillation of said pallet lever between said banking stops.

2. In an escapement mechanism for watch movements, a mainspring-driven escape wheel, an oscillatory pallet lever formed at one end with a yoke having engagement with teeth provided on the periphery of the escape wheel, the opposite end of said lever being formed with spaced tines, spaced stationary banking stops limiting rocking movement of said pallet lever, a balance wheel staff, a circular disk roller movable in unison with said staff, a jewel pin on said roller arranged for alternate engagement with the tines of said pallet lever, said roller being formed with an arcuate guideway extending inwardly of the roller from its circular outer edge across one face of the roller to its central region about said staif, and a guard finger formed on the outer end of said pallet lever movable in said guideway during oscillation of said pallet lever between said banking stops, said linger being normally spaced from wall surfaces of said guideway when said pallet lever is in direct contact with one or the other of said banking stops.

3. In an escapement mechanism for watch movements, as defined in claim 1, and wherein said guard finger constitutes a continuation of one of the tines of said pallet lever.

4. In an escape mechanism for watch movements as defined in claim 1, and wherein the arcuate guideway on said disk roller is disposed in concentric reation to the axis of rocking movement of the pallet lever.

5. As a new article of manufacture, a disk roller for use in the escape mechanisms of watch movements, said roller including a circular body formed for axial connection with an associated oscillatorybalance wheel staff, an arcuate guideway extending inwardly of the roller from a circular outer edge across one face of the roller to the central region thereof about said staff, and a pallet lever engaging jewel pin projecting perpendicularly from a face of said roller body in which the guideway is formed.

JASON GLENN BISHOP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 220,849 Laughlin Oct. 21, 1879 710,823 Voigt I Oct. 7, 1902 1,359,005 Verner Nov. 16, 1920 

